a friend of mine worked on school busses the guy before him didnt maintain them he sat around all day and smoked cigarettes so when he finally got the job everything was in terrible shape these things are run hard too just about every day we would meet for beers after work he would always walk into the bar with some fucked up part in his hands obliterated bottom end bearing chewed up tranny gears spun wheel bearings everything you could imagine one of the busses was even being run with a missing piston apparently it threw a rod the guy pulled the head pulled the piston and conrod out put it back together with the ports blocked off and welded over the hole in the side of the block he said it had been running like that for months albeit low on power and a rough idle